In an information network, such as the Internet, user's computers, referred to as clients, request information from information-providers' computers, referred to as servers, and the servers supply the requested information to the clients. In the World Wide Web (WWW), which is a de-facto standard for storing, finding, and transferring information on the Internet, the information is supplied in the form of pages. A page is a display screen-full of information expressed in textual, graphical, scriptural, and/or other form. A page comprises one or more information objects. An object is an information element that has its own network address--preferably a unique single address--called a URL (Uniform Resource Locator). For example, a page may comprise one or more text objects, one or more picture objects, and one or more script objects that are presented on the display screen in a layout defined by a frame object.
Typically, a server has a main page that serves as the entry point to the information and services that the server provides. This page typically points to other pages and to objects (e.g., graphic images, video/audio/text files, etc.), which are typically served by the same server.
Generally, when a client accesses the server, the server provides the main page to the client and then interacts with the client to provide the client with desired additional information and/or services. As increasing numbers of clients access the server, the server's processing load increases and its performance eventually degrades, so that users experience increasing delays between the time at which they place a request to the server and the time at which their request is satisfied by the server.
To avoid overloading of a server, typically an administrator must manually reconfigure the server and redirect some of the requests to other servers in order to lessen the load on the subject server. Some service providers store replicas of the served information in a plurality of servers and have different ones of the servers serve different requests, e.g., on a round-robin basis, thereby spreading the load of requests over multiple servers. This has several disadvantages. Firstly, an administrator's manual intervention is slow, inefficient, prone to error, and often not prompt. Secondly, using a plurality of servers to serve requests on a round-robin basis results in underutilization of the servers during periods when relatively few requests are being made, and hence it is inefficient. Furthermore, it requires all server information to be replicated on each server; the servers cannot take advantage of a common cache for common data.